1. Field of the Invention
The present invention generally relates to crop harvesting equipment and, more particularly, is concerned with an axial flow combine rotor having helical threshing extension members spanning multiple spaced attachment sites disposed in helical rows in the forward threshing area of the axial flow rotor.
2. Description of the Prior Art
Combines for harvesting grain crops such as wheat, barley, oats and the like have been known for many years. The use of combines to harvest grain crops of this type has permitted the efficient production of grain grown on very large fields with minimum use of labor.
Progressively, combines have been developed which are capable of harvesting wider swaths of crop than previously and thus have resulted in recent combines being larger and more powerful, as well as more expensive, than earlier combines.
The increased cost of recent combines has also led to development of combines capable of harvesting a wider variety of grain crops than capable of being handled by earlier combines. This capability typically requires, at a minimum, the exchanging of one type of crop gathering header on the combine for another.
With respect to the threshing and separating mechanism of the combine, however, it is preferred that the mechanism be adapted to thresh and separate a wide variety of grain crops with the need to exchange only a bare minimum of harvesting elements. Adapting the mechanism to thresh and separate a wide variety of grain crops makes it necessary that the combine be able to handle crops varying in bulk, moisture content, toughness and other crop conditions.
One commercial axial flow combine, identified as the Case International Serial 1600 Axial-Flow Combine, employs a single, large-diameter, axial flow rotor to thresh and separate a wide variety of crops under a wide variety of crop conditions. The axial flow rotor, mounted longitudinally inline with the direction of travel of the combine and enclosed in a cylindrical cage, has a plurality of straight and helical rasp bars mounted about its exterior over a forward threshing area thereof which coact with concaves mounted to the cage to thresh the crop repeatedly as the crop is conveyed rearwardly. Also, the axial flow rotor has a plurality of straight separator bars mounted about its exterior over a rearward separating area thereof which coact with grates mounted to the cage to separate the grain from the threshed crop residue.
Recently, an improved axial flow rotor, referred to as a "specialty" rotor, has been introduced for use in the aforementioned Case International Serial 1600 Axial-Flow Combine. Apparently, the goal of the specialty rotor is to provide a single basic rotor designed to handle a variety of different crops. The rotor has a forward threshing area and a rearward separating area which together support a checkerboard pattern of multiple spaced-apart threshing and separating elements disposed in helical rows. The elements are individually mounted to the exterior of the rotor at respective spaced-apart single attachment sites. This prior art checkerboard pattern defines continuous helical criss-crossing paths extending from the entry end to the discharge end of the specialty rotor.
The specialty rotor appears to be a step in the right direction toward the goal of being able to provide a basic rotor designed to accommodate various crops and crop conditions. However, even this specialty rotor still falls short of reaching this goal. Under certain tough crop conditions, the checkboard pattern of single site threshing elements covering the forward threshing area of the specialty rotor promotes an augering-type flow of minimially-threshed crop material along the continuous helical paths which increases the amount of unthreshed grain conveyed through the tailings elevator of the combine and increases the horsepower and thereby the fuel required to operate the combine.
Consequently, a need exists for improvement of the adaptability of the threshing action of the axial flow specialty rotor to handle various crop and crop conditions.